Textile coloring apparatus with fluid motor interrupting means



Feb. 21. 1967 E. w. LAWRENCE ETAL 3,304,862 TEXTILE COLORING APPARATUS WITH FLUID MOTOR INTERRUPTING MEANS Filed July 17, 1964 4 sheets sheet l 21, 1967 Q E. w. LAWRENCE ETAL 3,304,862 Y TEXTILE COLORING APPARATUS WITH FLUID MOTOR INTERRUPTING MEANS Filed July 17. 1964 4 Sheets-Sheet 2 E. w. LAWRENCE ETAL 3,304,862 TEXTILE COLO NG APPARAT WITH FLUID NTE'RRUPTIN EANS RI MOTOR I Feb. 21, 1967 4 Sheets-Sheet 5 1 Filed July 17, 1964 Feb. 21, 1967 .w. LAWRENCE ETAL 3,304,852

' TEXTILE COLORING APPARATUS WITH FLUID MOTOR INTERRUPTING MEANS Filed J uly 17, 1964 4 Sheets-Sheet .4

United States Patent 3,304,862 TEXTILE COLORING APPARATUS WITH FLUID MOTOR INTERRUPTING MEANS Edward W. Lawrence, Johnston, RJL, and William H. Angevine, Hendersonville, N.C., assignors to Cranston Print Works Company, Cranston, R.I., a corporation of Rhode Island Filed July 17, 1964, Ser. No. 383,485 2 Claims. (Cl. 101-172) This invention relates to textile coloring apparatus for applying color to spaced portions of a moving sheet of yarn or the like.

In order to achieve a random multicolored pattern in woven or tufted textile material as in rugs, for example, it is necessary to provide a multicolor yarn having colors applied thereon in a random manner, that is, in a pattern having colors thereon in random lengths and with random distribution. As a ractical matter, a pattern which is sufliciently random for the stated purpose is produced by using an irregular yarn coloring pattern having a repeat length of about 50 to 100 feet. Since a sheet of yarns having a pattern of such a great repeat length cannot be printed by an engraved roll of practical diameter, one type of apparatus heretofore disclosed for random application of color to a sheet of yarns consisted of a series of generally horizontally spaced pairs of rolls, one pair for each color, the rolls of which pairs were moved toward and away from one another in a predetermined sequence by a suitable control system to apply color to spaced portions of the yarn sheet. Since, with such an arrangement, the pattern repeat was not limited by mechanical considerations such as roll sizes and spacings, but rather by a pattern belt, punched tape, or the like, the pattern repeat could readily be made sufficiently long for a suitably random pattern. Apparatus of such type is shown, for example, in Patent No. 2,573,097.

Although textile coloring apparatus of the type above described had great advantages in enabling the production of multicolor patterns having a much greater repeat length than was practical with engraved rolls, it created a number of problems.

The most serious of these problems had to do with the failure of such heretofore known apparatus adequately to support and control the sheet of yarns during its passage through the apparatus, with the result that color was applied not only in accordance with the predetermined pattern, but, because of uncontrolled sagging of the sheet as it moved through the apparatus, at other places as well, so that two or more colors were frequently superimposed, an obviously undesirable result.

Another serious problem had to do with the undesirable transfer by the yarn itself of color from a preceding pair of rolls to a succeeding pair of rolls which was followed by applying of the transferred color at the second pair of rolls, also causing undesirable superimposing of colors.

Still another problem had to do with the inability to achieve precise control of the application of colors to the yarn sheet in the predetermined pattern, so that gaps and overlaps as between different colors applied by the various roll pairs were created.

Accordingly, it is an object of the present invention to solve the above-mentioned and other problems by means of a unique textile coloring apparatus of the type having a series of horizontally spaced pairs of rolls operated in a predetermined sequence to color spaced portions of a sheet of yarns.

This is accomplished, according to a major aspect of the invention, by locating at least the upper rolls of each pair, herein referred to as yarn supporting rolls, and preferably the lower rolls, the coloring rolls, as well, in a 3,304,852 Patented Feb. 21, 1967 downwardly bowed curved plane maintaining a substantial peripheral wrap of the yarn sheet in contact with each of the supporting rolls at all times during the operation of the apparatus. By utilizing this arrangement according to the invention, the application of a relatively low tension to the yarn sheet positively prevents drooping of the yarn sheet with possible unwanted pickup of color from an underlying coloring roll. Furthermore, in apparatus according to the invention wherein the lower coloring roll is fixed and the upper supporting roll movable toward it for coloring, each of the supporting rolls in its upwardly retracted inoperative position is spaced downwardly toward its cooperating coloring roll out of a generally horizontal plane defined by the lower yarn supporting surfaces of the next adjacent yarn supporting rolls in their downwardly advanced operative positions. This arrangement ensures maintaining the yarn sheet in contact with a said supporting roll in its upward retracted inoperative position while between next adjacent supporting rolls in their downwardly advanced operative position, in order that a precisely colored pattern may be produced free from gaps and overlaps at the edges of the color patterns.

According to another aspect of the invention, also directed to the precision of the colored pattern, with apparatus according to the invention employing movable supporting rolls and fixed coloring rolls, means are employed for defining a predetermined operative position of the upper supporting rolls and providing spacing between the opposing supporting and coloring rolls in their operative positions, making it possible to utilize metallic supporting and coloring rolls if desired. In this regard, too, the coloring rolls are preferably vertically adjustable as to their fixed positions.

According to still another aspect of the invention, novel means are employed to prevent coloring the yarn sheet with transferred color carried on a succeeding supporting or guiding roll, such being accomplished according to the invention by cleaning means associated with each supporting roll to remove therefrom any color transferred thereto and prevent further transfer of removed color either to the yarn sheet, or the underlying coloring roll mechanism including its color box which contains a supply of coloring material. In this regard, trough means are provided for conducting removed color axially of the supporting roll beyond its working surface to prevent its possible contamination of the underlying yarn and coloring roll mechanism.

For the purpose of fully explaining further objects and features of the invention, reference is now made to the following detailed description of a preferred embodiment thereof, together with the accompanying drawings, in which:

FIG. 1 is an overall side view of to the invention;

FIG. 2 is an end sectional elevation view, partly broken away, of a portion of the apparatus of FIG. 1, taken on the line 2-2 of FIG. 1;

FIGS. 3, 4 and 5 are partial side sectional elevational views of portions of the apparatus of FIG. 1, taken on the lines 3-3, 4-4 and 5-5, respectively, of FIG. 2;

FIG. 6 is a partial sectional plan view of a portion of the apparatus of FIG. 1, taken on the line 66 of FIG. 2;

FIG. 7 is a partial sectional side detail elevational view of a portion of the apparatus of FIG. 1, taken on the line 77 of FIG. 2;

FIGS. 8 and 9 are sectional side views showing the upper supporting roll and lower coloring roll of a roll apparatus according pair in their inoperative and operative positions respectively;

FIG. 10 is a sectional side view showing a series of three successive roll pairs with their upper supporting rolls in successive operative, inoperative, and operative positions and;

FIGS. 11 and 12 are, respectively, top and partial side views of a control system for use with the apparatus of FIG. 1.

In the drawings are shown four pairs of rolls 14-15, 16-17, 18-19, and 20-21, together with input guide rolls 22, 23, 24 and output guide roll 25 arranged in a generally horizontal series for coloring the yarns of a yarn sheet Y with different colors successively on different spaces in a predetermined periodically recurring pattern. A dryer having conveying rolls 26, 27, 28, 29, herein shown as including two flights and utilizing any suitable drying medium such as hot air, is preferably provided for drying the yarn sheet immediately after coloring. Suitable drives are provided for rotating all of the rolls for moving said sheet of yarns through the apparatus, and a control mechanism is provided as well for controlling the roll operation for coloring.

In accordance with the present invention, there is provided a series of at least three generally horizontally arranged upper yarn supporting rolls 14, 16, 18 and 20, each rotatable about a vertically movable axis providing at the lower portion of their peripheries a series of yarn supporting surfaces generally horizontally spaced from one another between the input roll 24 and output roll 25 and arranged in a downwardly bowed horizontal plane B between the input and output guide rolls. Likewise there is provided a cooperating series of at least three generally horizontally arranged lower yarn coloring rolls 15, 17, 19, 21, each rotatable about an adjustably fixed axis providing at the upper portion of their peripheries a series of yarn coloring material carrying surfaces also arranged in a downwardly bowed horizontal plane B between the input and output guide rolls. The yarn supporting and coloring rolls thus provide a series of horizontally spaced pairs of rolls located in a generally horizontal downwardly bowed plane B to maintain a substantial peripheral wrap of the yarns of said sheet about each of the supporting rolls at all times during the operation of the apparatus. Means, hereinafter more fully described, are provided for moving each of the supporting rolls 14, 16, 18, 20 through a vertical distance V, upwardly away from its cooperating coloring roll 15, 17, 19, 21 to a retracted inoperative position supporting said sheet of yarn out of contact with said coloring roll (FIGS. 2-5, 8) and downwardly toward said coloring roll to an advanced operative position supporting the yarn sheet in contact with coloring material on a cooperating coloring roll, for coloring yarn sheet Y interposed therebetween. Each of the supporting rolls is positioned in its upwardly retracted inoperative position while between adjacent supporting rolls in their downwardly advanced operative position such that the lower yarn supporting surface of each of the supporting rolls in its upwardly retracted inoperative position is spaced downwardly toward its cooperating coloring roll out of a generally horizontal plane P defined by the lower yarn supporting surfaces of the next adjacent yarn supporting rolls both in their downwardly advanced operative position (FIG. 10). The supporting rolls are also located in a predetermined advanced operative position providing a clearance C between the surface of the opposed roll of a pair, which clearance can be adjusted by adjusting the fixed position of the coloring rolls.

Each of the pairs of supporting and coloring rolls 14- 15, 16-17, 18-19, 20-21 is mounted on its individual pair of roll stands, generally designated 32, 34, 36, 38, respectively, which pairs of roll stands differ only in the vertical height at which the pair of rolls carried thereby is supported in order to provide their locations in a downwardly bowed plane B characteristic of the present invention. A similar input roll stand is provided carrying the three input rolls 22, 23, 24. The output roll 25 and dryer rolls 26-29 are supported by dryer frame elements.

A typical one of the pairs of roll stands 32, is shown in its entirety in FIG. 2 and as to portions thereof in FIGS. 3 through 7. In general, it includes side members 42, 43 supporting opposite ends of the pair of rolls 14, 15 and their associated elements extending between said members, color box 60 and its associated adjusting rod 62 and transverse support 64, clearer plate 80 and its associated support bar 82 and through 84, and eccentric lifting shaft 100.

More specifically, lower coloring roll 15 has its bearings 66, 68 mounted on color box 60 at the ends thereof, said bearings and the ends of said color box in turn being mounted in vertically adjustable fixed position by means of pairs of opposed wedge elements 67, 69 mounted on transverse support 64. The upper of said wedge elements are movable toward and away from one another by a threaded rod 62 having a handle 70 which can be manually rotated for vertical adjustment of coloring roll 15 and its color box 60. Upper supporting roll 14 is mounted at its ends by bearings 76 carried by horizontally extending brackets 74, said brackets at their other ends being mounted for swinging movement on stub pivot shafts 72 supported in suitable bearings 73 mounted on side members 42, 43. Eccentric shaft 100 is provided for swinging supporting roll 14 about pivot shafts 72 to and from the operative and inoperative position of the supporting roll 14 relative to its cooperating coloring roll 15. Said shaft is moved vertically by motor 104 from its upper inoperative position shown in full lines in the FIGURES 2 and 3 to its lower operative position shown in dashed lines. The eccentric shaft 100 is connected at the ends thereof to roll 14 by means of metal tapes 77 which extend between bearings 76 and 78 On roll 14 and shaft 100, respectively. If desired, helper springs 79 may be connected between roll bearings 76 and each of side members 42, 43.

Roll stand 30 has mounted thereon a conventional three roll stack including rolls 22, 23, 24 about which the yarn sheet is passed in a convoluted path to nip the yarn sheet Y there-between for control of tension by the succeeding rolls.

Roll driving means are provided within member 43 in the form of bevel gears, lower bevel gear 44 rotating coloring roll 15 through universal drive element 46 and upper bevel gear 48 rotating supporting roll 14 through universal drive element 47. All of bevel gears 44 and 48, respectively, including a similar one of said gears in input roll stand 30, are interconnected by universally jointed shafts 46, 47, respectively, which in turn are driven by the separately adjustable outputs of a variable speed drive 50, which also drives output roll 25 and dryer rolls 26, 27, 28, 29. Motor 51 drives said variable speed drive 50 as well as control system 124 through its variable speed drive 140.

For cleaning each of the supporting rolls 14, 16, 18, 20, as Well as output roll 25 and dryer rolls 26, 27, 28, 29 to prevent transfer of color thereby, there is provided a doctor blade 80 extending therealong, said doctor blade having an underlying trough 84 and an overlying support bar 82, the blade being loosely mounted therebetween by bolts 83 and spacers 85 which are received within an oversize bore 87 in plate 80. A plurality of hairpin springs 81 are mounted on bar 82 by said bolts 83, with their free ends in contact with doctor blade 80 to press the free end of said blade firmly against the supporting roll 14 to remove color material therefrom for discharge into trough 84 and fiow therealong for discharge at the ends of the trough beyond the working roll surfaces into a funnel 88 so that removed color cannot contaminate the yarn sheet, the coloring roll or the color material contained in color box 60. The doctor blade support bar 82 is adjustably mounted at its ends in brackets 90 which are rotatably mounted on pivot shafts 72, the brackets 90 having adjusting handles 92, 94 for adjustably positioning support bar 82 as desired. Spring 96 extends between brackets 90 and roll bearings 76 to hold the brackets and the support bar carried thereby in position, but may be released in order that doctor blade 80 may be swung out of its operating position if such be desired.

Eccentric lifting shaft 100 is mounted at its one end in a suitable bearing 102 in side member 43 and at its other end is mounted on pin 101 of and driven by a half revolution air motor generally designated 104, such motor having associated therewith an air valve 106 electrically operated by current supplied through wires 108 by control system 124 as hereinafter more fully described. Compressed air is supplied to'said valve through air line 110.

As shown in FIG. 7, air motor 104 has three pistons, a dead center piston 112 and a pair of side pistons 114, 116 coaxial with and axially spaced from each other and perpendicular to the axis of piston 112. A central crankshaft 118 is provided having a piston crank pin 119, to which are connected pistons 112, 114, 116 by their links 113, 115, 117, respectively. Eccentric pin 101 of square cross section is also mounted on the face of crankshaft 118 to be received within a square recess in the end of lifting shaft 100 for moving it through its vertical travel V. Air is supplied through passages in the housing of air motor 104 to dead center piston 112, through connected axial and radial passages in pistons 114, 116, such that a piston in its retracted position away from crankshaft 118 provides an air passage connection to the dead center piston, while a piston in advanced posit-ion toward crankshaft 118 cuts oif the air supply to dead center piston 112. Valve 106 selectively connects one of said pistons 114, 116 and its axial passageway to a source of air under pressure supplied at inlet pipe 110, and the other of said pistons and its said passageway to exhaust.

To operate the motor 104 with the elements of the valve 106 and the motor 104 positioned as shown in FIG. 7, with lifting shaft pin 101 in its upper position (the inoperative position of supporting roll 14), air pressure supplied through the passage 121 in piston 116 will move dead center piston 112 downwardly off dead center. The crankshaft 118 will then be moved a half revolution by piston 116, cutting off the air supply to dead center piston 112. The rotary motion of crankshaft 118 will cease withpiston 116 fully advanced and piston 114 fully related, with the lifting shaft pin at 10102 and the eccentric at 100a (the operative position of supporting roll 14). The reverse half cycle is accomplished by turning valve 106 to connect inlet 110 to piston 114 and its passage 122.

In order to operate valves 106 in a predetermined sequence, their electrical input wires 108-1, 108-2, 108- 3, 108-4 are connected to control system 124 best shown in FIGS. 11 and 12, having four microswitches 125-1, 125-2, 125-3, 125-4, operated by four pattern belts 127- 1, 127-2, 127-3, 127-4 which are synchronously driven by motor 51 through variable speed drive 140. The pattern belts are several feet in length, being trained around pulleys 132-137 and driven by sprocket pulley 137, a spring 138 being utilized in association with idler pulley 134 to tension its belt 127. The belts are driven at a speed much lower than that of the movement of the yarn Y so that a pattern repeat of lengths much longer than that of the yarn sheet within the apparatus is readily provided.

In operation of the apparatus herein described and shown in its entirety in FIG. 1, a sheet of yams Y is moved through the apparatus as its rolls are rotated by motor 51 tensioned as by operating the output and driver rolls at a slightly higher surface speed than the input rolls, with the supporting rolls being rotated at the same speed as that of sheet Y and the coloring rolls at a somewhat higher speed. The unique downwardly bowed arrangement of the pairs of rolls according to the present invention, ensures that the yarn sheet Y is securely maintained in contact at all times with all of the supporting rolls. Thus, when one or more of the supporting rolls is moved either downwardly or upwardly to and from its operative coloring position in response to signals from the control system, such movement will occur precisely, and, due to the air motors 104, with great rapidity, so that the precise pattern desired will be produced, without the disposition of unwanted additional color on the yarn sheet as would occur where the yarn sheet to sag downwardly away from a supporting roll as is likely to occur upon the termination of a coloring sequence, and without the creation of overlaps or gaps between successive colors as will occur with imprecise roll movement in response to a coloring signal.

At the same time, marking of the yarn sheet by transfer of colors from a supporting roll is prevented by the utilization of a doctor blade in each of the supporting rolls and including the output and dryer rolls, until the yarn sheet becomes sufliciently dry so that color will no longer be transferred by the yarn sheet to a succeeding roll.

As an important aspect ofthe invention, the provision of clearance between the supporting and coloring rolls of a roll pair while in their operative position makes possible the utilization of steel roll pairs, thus making it possible to clean the supporting rolls with the doctor blades as well as improve the precision in coloring. In this regard, the establishment of a predetermined opera tive position of the supporting roll spaced from the coloring roll, combined with the coloring roll adjustment provided by its wedges, makes it possible to establish the precise clearance desired, usually slightly less than the thickness of the yarns in the yarn sheet.

Thus, it will be seen that the invention provides novel apparatus of the type having a series of generally horizontally spaced pairs of rolls, each movable by a suitable control system in a predetermined sequence to color spaced portions of a yarn sheet, the apparatus according to the invention having a number of important aspects which provide improved performance over heretofore known apparatus. Various modifications of the preferred apparatus herein described, within the spirit of the invention and the scope of the appended claims, will be apparent to those skilled in the art.

What is claimed is:

1. A textile coloring machine comprising:

at least three printing couples, each said couple including a metallic, upper, yarn supporting roll and a metallic, lower, yarn coloring roll,

said supporting and coloring rolls being disposed in a horizontally spaced and downwardly bowed path, the yarn to be colored being passed between the convex surface formed by the lower portions of said supporting rolls and the concave surface formed by the upper portion of said coloring rolls,

means to rotate each of said rolls,

a horizontally movable adjustment member for setting the vertical position of each said coloring rolls,

arms, pivotally secured to said machine, for rotatably mounting each of said supporting rolls,

a drive shaft,

a member eccentrically connected to said drive shaft and to said supporting arms, for moving said supporting roll to and from said coloring roll,

a fluid motor for rotating said drive shaft between a first position whereby said supporting roll is in a retracted inoperative position supporting said yarn out of contact with said coloring roll and a second position supporting said yarn in contact with said coloring roll,

a first piston movable in a first cylinder for driving said shaft,

an aperture in said first cylinder,

a second cylinder and a second piston movable therein for driving said shaft, and a third cylinder and a third piston movable therein for driving said shaft, said first, second and third pistons each having a connecting rod connected to a common eccentric point on said drive shaft, said second and third pistons being relatively positioned so that they move in opposite direction to one another and transversely to the movement of said first piston so that when said shaft is in said first position said second piston is in 8 a switch for controlling said valve of each printing couple; and a programmed drive mechanism for actuating said switches in a predetermined pattern for a predea fully retracted position away from said shaft and termined time.

when said shaft is in said second position said third References Cited by the Examiner piston is in a fully retracted position away from said shaft, said first piston being in a dead center location TE T E ATENTS at said first and second positions of said shaft,

a first duct connecting said aperture in said first cylinder 2 3:3 2 2 WOPdWOYth to said second cylinder and a second duct connecting 3 1 2 3 10118 said aperture in said first cylinder to said third cylin- 3; x32 fig z i i i l d 1 J a 5 2 2,240,249 4/1941 Wichwire l01178 a first conduit connecting said second cylinder to said 53 11/1941 Wlchwlre 1015482 valve, and a second conduit connecting said third gii g g 'f cylinder to said valve, and 1 a first passage through said second piston for connect- 2,573,097 10/1951 Epstem 68 203 ing said first duct to said first conduit when said pis- 2,606,493 8/1952 Haspert 101*247 X tons are in a first position, and a second passage 2,639,666 3/1953 Haney 101*247 through said third piston for connecting said econd 35081640 4/1963 Mllner 101172 duct to said second conduit when said pistons are in FOREIGN PATENTS a second position,

said valve selectively connecting one of said conduits 640,241 12/1936 Germany' to a source of pressurized fluid while connecting the ROBERT E. PULFREY, Primary Examiner.

J. R. FISHER, Assistant Examiner.

other of said conduits to an exhaust outlet. 2. The machine of claim 1 further comprising, a control system for operating said valve including: 

1. A TEXTILE COLORING MACHINE COMPRISING: AT LEAST THREE PRINTING COUPLES, EACH SAID COUPLE INCLUDING A METALLIC, UPPER, YARN SUPPORTING ROLL AND A METALLIC, LOWER, YARN COLORING ROLL, SAID SUPPORTING AND COLORING ROLLS BEING DISPOSED IN A HORIZONTALLY SPACED AND DOWNWARDLY BOWED PATH, THE YARN TO BE COLORED BEING PASSED BETWEEN THE CONVEX SURFACE FORMED BY THE LOWER PORTIONS OF SAID SUPPORTING ROLLS AND THE CONCAVE SURFACE FORMED BY THE UPPER PORTION OF SAID COLORING ROLLS, MEANS TO ROTATE EACH OF SAID ROLLS, A HORIZONTALLY MOVABLE ADJUSTMENT MEMBER FOR SETTING THE VERTICAL POSITION OF EACH SAID COLORING ROLLS, ARMS, PIVOTALLY SECURED TO SAID MACHINE, FOR ROTATABLY MOUNTING EACH OF SAID SUPPORTING ROLLS, A DRIVE SHAFT, A MEMBER ECCENTRICALLY CONNECTED TO SAID DRIVE SHAFT AND TO SAID SUPPORTING ARMS, FOR MOVING SAID SUPPORTING ROLL TO AND FROM SAID COLORING ROLL, A FLUID MOTOR FOR ROTATING SAID DRIVE SHAFT BETWEEN A FIRST POSITION WHEREBY SAID SUPPORTING ROLL IS IN A RETRACTED INOPERATIVE POSITION SUPPORTING SAID YARN OUT OF CONTACT WITH SAID COLORING ROLL AND A SECOND POSITION SUPPORTING SAID YARN IN CONTACT WITH SAID COLORING ROLL, A FIRST PISTON MOVABLE IN A FIRST CYLINDER FOR DRIVING SAID SHAFT, AN APERTURE IN SAID FIRST CYLINDER, A SECOND CYLINDER AND A SECOND PISTON MOVABLE THEREIN FOR DRIVING SAID SHAFT, AND A THIRD CYLINDER AND A THIRD PISTON MOVABLE THEREIN FOR DRIVING SAID SHAFT, SAID FIRST, SECOND AND THIRD PISTONS EACH HAVING A CONNECTING ROD CONNECTED TO A COMMON ECCENTRIC POINT ON SAID DRIVE SHAFT, SAID SECOND AND THIRD PISTONS BEING RELATIVELY POSITIONED SO THAT THEY MOVE IN OPPOSITE DIRECTION TO ONE ANOTHER AND TRANSVERSELY TO THE MOVEMENT OF SAID FIRST PISTON SO THAT WHEN SAID SHAFT, SAID FIRST PISTON BEING IN A DEAD CENTER LOCATION A FULLY RETRACTED POSITION AWAY FROM SAID SHAFT AND WHEN SAID SHAFT IS IN SAID SECOND POSITION SAID THIRD PISTON IS IN A FULLY RECTRACTED POSITION AWAY FROM SAID SHAFT, SAID FIRST PISTON BEING IN A DEAD CENTER LOCATION AT SAID FIRST AND SECOND POSITIONS OF SAID SHAFT, A FIRST DUCT CONNECTING SAID APERTURE IN SAID FIRST CYLINDER TO SAID SECOND CYLINDER AND A SECOND DUCT CONNECTING SAID APERTURE IN SAID FIRST CYLINDER TO SAID THIRD CYLINDER, A VALVE, A FIRST CONDUIT CONNECTING SAID SECOND CYLINDER TO SAID VALVE, AND A SECOND CONDUIT CONNECTING SAID THIRD CYLINDER TO SAID VALVE, AND A FIRST PASSAGE THROUGH SAID SECOND PISTON FOR CONNECTING SAID FIRST DUCT TO SAID FIRSTCONDUIT WHEN SAID PISTONS ARE IN A FIRST POSITION, AND A SECOND PASSAGE THROUGH SAID THIRD PISTON FOR CONNECTING SAID SECOND DUCT TO SAID SECOND CONDUIT WHEN SAID PISTONS ARE IN A SECOND POSITION, SAID VALVE SELECTIVELY CONNECTING ONE OF SAID CONDUITS TO A SOURCE OF PRESSURIZED FLUID WHILE CONNECTING THE OTHER OF SAID CONDUITS TO AN EXHAUST OUTLET. 